The grinding machine of the prior art basically consists of a headstock and a tailstock between which is mounted the workpiece for rotary motion. The workpiece typically is a steel roll used in the paper or steel industry which must be ground to a generally cylindrical shape within extremely precise tolerances. A grinding wheel is mounted for rotation on a subbase which can be moved towards and away from the roll. The subbase in turn is mounted for such sliding motion on a carriage which may be translated along the length of the workpiece. In order to provide a fine adjustment to the grinding wheel infeed, the wheel is mounted on a structure called the wheelhead. The wheelhead of the prior art comprises a large cast structure which is mounted to the subbase for pivotal motion transverse to the longitudinal axis of the roll. By pivoting the wheelhead about its axis which is offset from the grinding wheel axis, infeed movement of the grinding wheel may be obtained.
A majority of the equipment associated with the driving and control of the grinding wheel are mounted on the wheelhead thereby creating an element in the machine having a significantly large mass. Although the advantages of this type of infeed are significant, the structure is inherently dynamically soft. The predomiant dynamic forces on the wheelhead act in a horizontal direction as a result of the forces acting between the grinding wheel and the roll. The most significant structure in opposition to these forces is the bearing surface at the pivot axis of the wheelhead. This fact coupled with the large mass of the wheelhead creates a serious problem in obtaining an accurate surface finish on the roll.
These same factors are true with respect to the static forces which will also cause problems in limiting accuracy, but to a lesser extent.
It is, therefore, the purpose of this invention to substantially reduce the mass of the wheelhead assembly while increasing the bearing surfaces which are responsive to the dynamic and static forces.